Perform the already past expiration time check before updating
cvp->cv_mutex with the provided mutex. This check only depends
on local state. Doing it first ensures that cvp->cv_mutex will not
be updated in the timeout case or if it's ever called with an
expire_time <= now.
Reviewed-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#616
2ded1c7eff